首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   244615篇
  免费   56580篇
  国内免费   11371篇
耳鼻咽喉   2989篇
儿科学   6415篇
妇产科学   2660篇
基础医学   33367篇
口腔科学   8391篇
临床医学   33388篇
内科学   45560篇
皮肤病学   9102篇
神经病学   20490篇
特种医学   8447篇
外国民族医学   58篇
外科学   29138篇
综合类   32650篇
现状与发展   35篇
一般理论   37篇
预防医学   17708篇
眼科学   5108篇
药学   24772篇
  204篇
中国医学   12605篇
肿瘤学   19442篇
  2024年   1235篇
  2023年   2904篇
  2022年   7051篇
  2021年   10061篇
  2020年   11742篇
  2019年   15734篇
  2018年   15389篇
  2017年   16495篇
  2016年   16782篇
  2015年   19393篇
  2014年   21007篇
  2013年   21558篇
  2012年   17947篇
  2011年   18637篇
  2010年   19098篇
  2009年   13626篇
  2008年   12110篇
  2007年   10752篇
  2006年   9803篇
  2005年   8659篇
  2004年   6718篇
  2003年   6228篇
  2002年   5622篇
  2001年   4571篇
  2000年   4034篇
  1999年   3165篇
  1998年   1810篇
  1997年   1746篇
  1996年   1355篇
  1995年   1263篇
  1994年   1065篇
  1993年   657篇
  1992年   738篇
  1991年   646篇
  1990年   558篇
  1989年   474篇
  1988年   367篇
  1987年   363篇
  1986年   276篇
  1985年   207篇
  1984年   143篇
  1983年   97篇
  1982年   65篇
  1981年   55篇
  1980年   38篇
  1979年   65篇
  1978年   22篇
  1974年   18篇
  1970年   19篇
  1966年   20篇
排序方式: 共有10000条查询结果,搜索用时 10 毫秒
101.
102.
103.
温针灸治疗颞下颌关节功能紊乱病36例   总被引:1,自引:0,他引:1  
目的:比较温针灸与口服西药治疗颞下颌关节功能紊乱病的疗效。方法:治疗组36例取下关、牵正、颊车、阿是穴、合谷(双)行温针灸,对照组口服地西泮、吲哚美辛。结果:治疗组治愈率80·6%、总有效率100%,对照组治愈率40·6%、总有效率78·1%,两组有非常显著性差异(P<0.01)。结论:温针灸治疗颞下颌关节功能紊乱病方法简单,疗效显著。  相似文献   
104.
持续压力超负荷对兔左心室细胞凋亡的影响   总被引:3,自引:1,他引:2  
OBJECTIVE: To study the effect of chronic pressure overload on the apoptosis of the left ventricle myocytes in rabbits. METHODS: Rabbit models of chronic pressure overload-induced heart failure were prepared in which dynamic changes of apoptotic myocytes in the left ventricle were observed by way of terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) assay. RESULTS: Only a few apoptotic cells was observed in the sham-operated group, while in the experimental group, the apoptotic left ventricle myocytes significantly increased after operation, presenting a peak level between day 3 and day 7. Seven days after the operation, the apoptotic myocytes began to decrease and till day 14, the apoptotic cell number had been smaller than that measured on day 1. When signs of heart failure set in, the apoptotic myocytes were again increased (P<0.001). CONCLUSION: During chronic pressure overload, myocyte apoptosis in the left ventricle is elevated at the early stages and undulates subsequently, with the peak occurring before hypertrophy is obvious.  相似文献   
105.
本文建立了体液中右旋儿茶素的RP-HPLC测定方法。采用C_(18)键合相硅胶为填料的固相提取柱进行样品预处理,右旋儿茶素的提取回收率为79.8%.应用二极管阵列检测器对色谱峰纯度进行鉴定。该法精密度好,方法回收率近100%,日内、日间的变异系数为2.4~5.6%,血浓69.6~1160 ng/ml范围内呈线性关系,r=0.9993。家兔静注右旋儿茶素18mg/kg,其药代动力学过程符合二室模型,分布相半衰期为0.129 h,消除相半衰期为1.19h。  相似文献   
106.
107.
African Americans experienced massive internal migrations that shifted more than 6 million Southern-born blacks to other sections of the United States over the past century, a trend that only recently has been reversed. Whenever mass migration takes place, there is an opportunity to examine the role of the native and relocated environments in the development of disease. This article examines those relationships for diabetes mellitus, a group of diseases that disproportionately affect African-Americans relative to other racial and ethnic groups in the United States. Age-specific and age-adjusted rates with 95% confidence intervals were calculated for males and females for combinations of five regions of birth and four regions of residence at time of death. Southern-born males had statistically significantly higher death rates from diabetes than did their counterparts who died in the same regions in 9 of 16 comparisons. For females, those born in the South had statistically significantly higher rates in 15 of 16 comparisons. The results of this study indicate that place of birth and early life experiences are statistically associated with diabetes mortality among African Americans regardless of place of residence at time of death.  相似文献   
108.
We studied the plasminogen activation system in tumor tissue by measuring the antigen level of the 2 plasminogen activators, tissue-type (t-PA) and urokinase-type (U-PA) and their inhibitors, plasminogen-activator inhibitors type-1 (PAI-1) and type-2 (PAI-2) in the tissue extracts of 43 human benign and malignant ovarian tumors. U-PA levels were significantly higher in malignant than in benign tumors. In addition, U-PA antigen levels were higher in the metastatic tissue of advanced disease (FIGO stage III) than in the primary localized tumor (FIGO stage I/II). Also PAI-1 concentrations tended to be higher in malignant than in benign tumors, but this difference was not statistically significant. In contrast, t-PA levels were lower in metastatic than in non-metastatic tumors, whereas PAI-2 levels were unrelated to the stage of ovarian malignancy. These results were integrated in a plasminogen-activation-dependent malignancy index (U-PA × PAI-1/t-PA). This index distinguished the different groups of benign ovarian tumors, localized and metastatic ovarian carcinomas better than U-PA levels. It could be useful as a prognostic indicator in ovarian cancer © 1993 Wiley-Liss, Inc.  相似文献   
109.
The aim of the present study was to determine if muscarinic acetylcholine receptor-mediated peristaltic rhythmogenesis in the rat oesophagus is a central motor program that can be generated without peripheral sensory support. In anaesthetized male Sprague-Dawley rats, pressure-ejection of glutamate (10–20 pmol) and muscarine (5–10 pmol) in the subnucleus centralis of the nucleus tractus solitarii (NTSC) evoked monophasic pressure waves and rhythmic oesophageal peristalsis, respectively, but did not change mean arterial blood pressure or respiration. Application of muscarine (50–100 pmol) to the NTS extraventricular surface evoked rhythmic multi-unit burst discharges in the compact formation of the nucleus ambiguus (AMBC) that led to oesophageal peristalsis in a phase-locked manner. Evoked rhythmic AMBC activity persisted during neuromuscular blockade with curare, although the peak frequency of individual bursts was decreased. In a brainstem slice preparation, intracellular and whole cell patch recordings from AMBC neurones during focal stimulation of the NTSC region with muscarine revealed rhythmic depolarizing waves that showed a pattern similar to that of rhythmic oesophageal peristalsis. The present findings support the concept that medullary circuits comprising premotor neurones of the NTSC are intrinsically capable of generating rhythmic oesophagomotor output, but are subject to a powerful modulation by peripheral sensory feedback.  相似文献   
110.
BACKGROUND AND PURPOSE: Birth certificates are a major source of population-based data often used in maternal and child health research, but their value depends upon the level of accuracy of the data. The purpose of this study was to assess the validity of the birth registry data in Taiwan. METHODS: Obstetric records of a total of 2779 infants born at a municipal hospital in Taipei between 1995 and 1997 were abstracted and linked to the Taiwan Birth Registry (TBR). Concordance was presented by agreement percentages for various birth characteristics including gender, birth order, birth weight, and gestational age. Concordance was further assessed using Cohen's k and sensitivity/specificity for both birth weight and gestational age, with both variables categorized according to their customary definitions. RESULTS: Missing data for specific items in the TBR ranged from 0% (gender) to 1.6% (birth order). The birth registry accurately reported all 4 selected items, with the highest and lowest concordance percentage noted for gender (99.0%) and gestational age (88.3%), respectively. The level of agreement indicated by the Cohen's k statistic ranged from 0.92 to 0.96 for birth weight and gestational age when both variables were treated as categorical variables. CONCLUSIONS: The TBR showed a low rate of missing information and high levels of validity for the elements frequently used in maternal and child health research in Taiwan.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号